1. Field of the Invention
The present invention relates generally to internal-intermittent-combustion engines, and, more specifically, to a sequential rotary piston engine.
2. Description of the Prior Art
Heat engines are classified as the external-combustion type (the working fluid is entirely separated from the fuel-air mixture, and heat from the products of combustion are transferred through the walls of a containing vessel or boiler), and the internal-combustion type in which the working fluid consists of the products of combustion of the fuel-air mixture itself. Nowadays, the reciprocating internal-combustion engine and the steam turbine are by far the most used types of heat engines with the gas turbine in wide use only for high-speed aircraft.
Fundamental advantages of the reciprocating internal-combustion engine over power plants of other types are the absence of heat exchangers in the working fluid stream, the parts of the internal-combustion engine can work at temperatures well below the maximum cyclic temperature, a lower ratio of power-plant weight and bulk to maximum output (possibly except in the case of units of more than 10,000 hp), mechanical simplicity, and the cooling system handles a small quantity of heat.
The advantages of the reciprocating internal-combustion engine are of special importance in the field of land transportation, where small weight and bulk of the engine and fuel are always essential. In our present civilization the number of units and the total rated power of internal-combustion engines in use is far greater than that of all other prime movers combined.
The reciprocating internal-combustion engine dates back to 1876 when the German engine pioneer, Nikolaus Otto, developed the spark-ignition engine, and 1892 when Diesel invented the compression-ignition engine. Since then, engines have experienced a continuous development as our knowledge of the engine process has increased, as new technologies appeared and as the demand for new types of engines arose.
Usually, in a intermittent internal-combustion engine, a major moving part, called a piston, slides backwards and forwards in a straight line, inside a cylindrical cavity called cylinder. Such movement causes a volume variation of the cavity formed by the piston and the cylinder, that is used to perform a two or a four-stroke cycle.
An alternative to the design of linear-reciprocating-internal-combustion engine is the rotary design. The advantages of rotary over reciprocating action are primarily a matter of compactness, geometry, weight and cost of manufacturing.
Even before Otto""s 119-year-old idea got its first positive results, some ideas like the Pump of Ramelli were developed. (Ramelli""s Pump, developed in the sixteenth century, is the oldest reference to this type of rotary machines). Many engines of this category have been built, but the only one that has been developed to the point of quantity production is the Wankel (used in a line of sports-type cars by Mazda of Japan), where a rotating member is arranged to vary the working volume by an eccentric motion within a non-circular space. The most difficult problem with this engine is that of sealing the combustion chamber against leakage without excessive friction and wear. This problem is far more difficult than that with conventional piston rings as a xe2x80x9cline of contactxe2x80x9d instead of a surface of contact is usually involved and the surfaces to be sealed are discontinuous, with sharp corners. The Wankel engine is indeed smaller and lighter and has less vibration than conventional engines of the same output. There is no evidence that it is cheaper to produce. The sealing problem seems to have been solved as far as reasonable durability is concerned, but there is evidence of considerable leakage. This defect and the attenuated shape of the combustion chamber are responsible for poor fuel economy as compared with the equivalent conventional engine.
The idea of engines which toroidal pistons rotate or reciprocate within toroidal cylinders has also been advanced (like the Scott""s Omega engine in the 1960""s, where pistons reciprocate in a toroidal cylinder by means of a complex arrangement of cranks and shafts). The difficulties of connecting such pistons to the output shaft by a simple and reliable mechanism, together with the problem of sealing the sliding surfaces involved, caused the abandonment of such ideas.
Examples of such rotary engines are provided in the prior art. For example, U.S. Pat. Nos. 3,186,383; 3,937,187; 4,035,111 and 5,242,288 all are illustrative of such prior art. While these units may be suitable for the particular purpose to which they address, they would not be as suitable for the purposes of the present invention as heretofore described. Furthermore, whatever the merits, features and advantages of the above cited references, none of them achieve or fulfill the purposes of the Sequential Rotary Piston Engine (S.R.P.E.) of the present invention.
This invention concerns internal combustion engines and more particularly relates to rotary engines. This invention includes an output shaft, a body member mounted for rotation about the axis of the shaft, a plurality of annular cavities within the body member having a center of curvature on the rotational axis of the body member, an arcuate piston in each cavity, connector means secured to the pistons transmitting motion of the pistons to the output shaft, inlet means in the chambers whereby fuel may be applied to the combustion chambers between the pistons and end faces of the cavities, means for removing burnt gases from the chambers, first unidirectional clutch means between the body member and a fixed support, second unidirectional clutch means between the connector means and a fixed support, third unidirectional clutch means between the body member and the output shaft, fourth unidirectional clutch means between the connector means and the output shaft, the first and second unidirectional clutch means preventing motion of the body member and connector means relative to the fixed support in the reverse sense of the output shaft, the third and fourth clutch means allowing overrun of the output shaft relative to the body member or connector means.
U.S. Patent Number 3,937,187
A toroidal cylinder is provided with a slot formed around the inner wall. A central shaft carries a sun wheel engaging a set of planet gears which in turn engage a fixed ring gear secured to the cylinder adjacent the slot. A pair of rings are provided carrying sets of pistons running within the cylinder, the edges of the rings sealably running within the slot. Pins on the planet gears engage slotted arms secured to the rings so that opposite pairs of pistons move toward and away from one another in sequence thus providing compression and expansion strokes in the cylinder together with intake and exhaust strokes. A fuel mixture ignited by spark plugs or the like may be used or, alternatively, fuel injection may be utilized and inlet and exhaust ports are formed within the walls of the toroidal cylinder.
A rotary engine having a toroidal chamber which is stationary, and in which the pistons convey power to a common crankshaft under the control of a four-bar linkage including novel means for preventing reverse motion of any piston in the chamber. Inlet and exhaust valves to control the flow of energizing fluid are provided, and are actuated directly from the crankshaft. Novel sub-components include the four-bar linkage, the valve mechanism, and the arrangement by which rotary movement of the pistons in the chamber is eliminated.
An engine or pump is described which has a round cylinder in cross section, the surface of the cylinder being a round toroidal tube in the rotary direction. Fhe cylinder is made of two equal parts, one part fixed and one part rotating with each part meeting on a flat surface at a right angle to the drive shaft. Force exerted axially against the rotating cylinder where the two parts meet on the flat surface. The spring diaphragm is pre-loaded by a thrust bearing in a pre-loading disk to apply force to the rotating part of the cylinder. Within the cylinder are one or more round toroidal section pistons that are attached to the rotating part of the cylinder by piston pins. A hinged internal cylinder abutment is actuated by the piston as the piston passes through the abutment section. Working fluid to the cylinder is controlled by an internal valve actuated by a cam-disk on the drive shaft.
The present invention relates generally to internal-intermittent-combustion engines, and, more specifically, to toroidal rotary engines.
A primary object of the present invention is to provide a toroidal rotary engine that will overcome the shortcomings of prior art devices.
Another object of the present invention is to provide a toroidal rotary engine which is smaller, lighter, more completely free of vibration, cheaper, and mechanically simpler than the reciprocating linear internal-combustion engine.
A further object of the present invention is to provide a toroidal rotary engine including a simple control mechanism, an acceptable sealing of the sliding surfaces involved, and a reliable and simple connection between the toroidal pistons and output shaft.
A yet further object of the present invention is to provide a toroidal rotary engine that allows the fitness of a two or a four-stroke cycle with a spark-ignition or a compression-ignition system.
Another object of the present invention is to provide a toroidal rotary engine that is simple and easy to use.
A still further object of the present invention is to provide a toroidal rotary engine that is economical in cost to manufacture.
The foregoing and other objects are achieved by placing an even number of toroidal pistons (of identical size) into a closed toroidal cavity. The entire toroidal cavity is divided into smaller cavities or chambers according to the chosen even number of toroidal pistons (the size of the pistons are designed to fit into the toroidal cavity in order to provide a sealing action of the resulting cavities in relationship with their adjacent ones), and the actual working volume of the engine is the volume of the whole toroidal cavity less the volume occupied by the chosen even number of toroidal pistons. The toroidal pistons are arranged in two identical groups. Each of the two identical groups comprises one half of the even number of toroidal pistons placed symmetrically around the 360xc2x0 of the toroidal axis and connected to each other by a rigid connecting structure. The toroidal pistons belonging to one of the two identical groups are caused to move with solidarity as they are attached to the connecting rigid structure. This implies that when both groups are placed inside the toroidal cavity, the toroidal cavity is divided into an even number of smaller cavities or chambers equal to the chosen even number of toroidal pistons. Specific static areas of the entire static toroidal cavity are chosen to perform a specific action of the selected cycle of the engine (like the intake and the exhaust areas). If one of the two identical rigid symmetrical groups of toroidal pistons remains static by the action of a simple control mechanism in a specific place of the toroidal cavity, while the other one rotates inside the entire toroidal cavity (the movement caused by the pressure changes within the cavities or chambers of the engine due to burning the selected mixture of air and fuel), the toroidal cavities, formed by the placing of the two groups of toroidal pistons inside the entire toroidal cavity, experience a volume variation (half of the total even number of toroidal cavities will increase their volume and, obviously, the remaining cavities will diminish their volume). A relation of design is established between the maximum and minimum allowed volume for the toroidal cavities (it is also performed by the control mechanism). The motion of the free group starts when the relation of volumes is in the maximum for half of the toroidal cavities while, of course, in the minimum for the other half of toroidal cavities and, the position of the toroidal pistons and toroidal cavities matches with the position of the specific zones of the entire toroidal cavity in order to perform a cycle.
The moving group of toroidal pistons moves into the entire toroidal cavity until the toroidal cavities that were at the allowed maximum volume at the beginning of the motion diminish their volume to the established minimum. This implies that the toroidal cavities that were at the allowed minimum volume at the beginning of the motion, now are at the established maximum volume. After reaching this point, the control mechanism allows both groups of toroidal pistons to move together (which implies that there is no volume change in the toroidal cavities), performing a replacement action, (this means that all the toroidal pistons and all the toroidal cavities move in order to match with the static areas of the toroidal cavity to perform a new cycle).
Now, the group that was static in the previous cycle moves, while the group of toroidal pistons that was in motion in the previous cycle is static. The volume variations in the toroidal cavities are used to fix and perform a selected cycle (a two-stroke-cycle or a four-stroke-cycle). The groups of toroidal pistons describe a non-reciprocating sequential rotary motion. These two symmetrical groups of toroidal pistons are connected to two output shafts which movement is rectified by any known means in order to obtain a continuous non-sequential rotary motion.
The even number of toroidal pistons, the size of them, as well as the chosen cycle, depend on many design criteria, but the total number of toroidal pistons to be used is:
for two-stroke-cycle:
P=2n, where n=1,2,3,4 . . .
for four-stroke-cycle:
P=2n, where n=2,3,4 . . .
xe2x80x83where P is the even number of toroidal pistons (equal to the number of chambers) to be used by the S.R.P.E.
Due to the fact that in the four-stroke-cycle the number of different strokes is 4 (intake, compression, power and exhaust strokes) the number of cavities formed by placing the even number of toroidal pistons inside the entire toroid must be a multiple of 4, and for the two-stroke-cycle case, the even number of cavities to be used must be multiple of 2 (compression and power strokes).
The reasoning behind these formulas will become apparent from the following detailed description.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
The features and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment of the invention, when read in connection with the accompanying drawings.
The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate one embodiment of the invention and together with the description, serve to explain the principles of the invention.
It should be noticed that the set of drawings includes all normal functions required in a complete internal combustion engine, this is, combustion chambers, pistons shafts to transmit the so created motion as well as a timing mechanism to coordinate it among the different parts of the machine. All starter, ignition and fueling systems can be accommodated by the common practices related herein.
Additional objects of the present invention will appear as the description proceeds.
A rotary engine including a static toroidal cavity having an inlet port for introducing fuel and air to the cavity and an outlet port for exhausting products of combustion from the cavity is disclosed by the present invention. A first power train including a first output shaft and a second power train including a second output shaft are located partially within the cavity and able to rotate in the first direction. A plurality of pistons are positioned around a perimeter of the toroidal cavity and between the first and second power trains. The plurality of pistons are movable with respect to the cavity and include a first set of pistons connected to rotate with the first power train and a second set of pistons connected to rotate with the second power train. The plurality of pistons defining a plurality of chambers therebetween. Combustion of a fuel air mixture within a first one of the plurality of chambers causes a fuel gas mixture to be introduced into a second one of said plurality of chambers through the intake port, combustion material to be exhausted from a third one of the plurality of chambers and one of the first and second drive trains to rotate in the first direction. A subsequent combustion of a fuel air mixture in one of the plurality of chambers causes the other of the first and second drive trains to rotate in the first direction, the first and second drive trains alternating movement upon subsequent combustions.
To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described within the scope of the appended claims.